Wrench

ABSTRACT

Pliers for positively gripping a selected work piece between substantially parallel gripping jaw surfaces, one of which is carried by a fixed handle, the other of which is carried by a pivoted toggle member mounted on an extension of the fixed handle for pivotal movement and adjustment toward and away from the jaw on the fixed handle, a handle pivotally connected to the toggle member and tensioning means connecting said handles and adjustment means on the fixed handle and having pivotal connection with the pivoted handle whereby the gripping effort on a selected work piece may be adjusted to secure a strong positive grip thereon without causing damage to the work piece.

[451 June 27, 1972 United States Patent Hoffman FOREIGN PATENTS OR APPLICATIONS [54] WRENCH ABSTRACT [21] AppLNo.; 124,071

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CHARLES F. HOFFMAN 8d4/raf 'n4 d@ 1%1 ATTORNEY sum auf 2 PATENTEUJuuz'! |972 FIG. 3

CHARLES F HOFFMAN BY^ *@AL/am ATTORNEY WRENCH NATURE AND OBJECT OF THE INVENTION The invention is an improvement in pliers in which an improved toggle connection between a fixed handle and jaw and the pivoted handle and jaw provides means for applying positive gripping pressure upon a work piece to be gripped between the jaws and then releasably locking the work piece while it is being gripped between the jaws when it is desired to release the piece.

By this invention and due to its unique construction, a large number of gripping and locking positions of the jaws may be employed for each adjustment of the stop screw in the fixed handle and through the link connecting these handles.

THE DRAWING FIG. l is a side elevation of the pliers embodying my invention showing the relative positions of the parts in solid lines when a selected work piece of relative small size is gripped and locked between the jaws; as shown in broken lines, the relative positions of the movable handle and link bar when the movable handle is in released position to remove the piece from the gripping jaws.

FIG. 2 is a view similar to that shown in FIG. 1 when a much larger work piece is gripped and locked between the jaws.

FIG. 3 shows another selection of adjustment of the movable jaws wherein its fulcrum is shown locked in a position intermediate the positions shown in FIGS. 1 and 2, along the slotted arm fixed to the fixed handle.

FIG. 4 is an enlarged fragmentary section taken in the direction of line 4-4 of FIG. 3.

DESCRIPTION As illustrated in the drawing of an embodiment of my invention, the plier consists essentially of a fixed handle 1 of channel form having a jaw portion 2 on the upper end thereof, and an adjustment screw 3 and blocking nut 4 carried on the opposite end, a channelled handle 5 pivotally connected at 6 with a member 7 having a second jaw cooperating with the jaw 2 for gripping a work piece W therebetween.

The handle 1 is provided with a rigid extension 9 protruding laterally in the direction of the member 7 and is slotted at l0 to receive a headed adjusting bolt ll carried by the extension 9 and which is movable along the slot to a desired position where it may be locked against sliding motion along the slot by means of a nut l2 threaded on to the bolt to compress a coiled spring 13 on the shank of the bolt engaging the base of the nut and the adjacent walls of the extension 9 as clearly shown in FIG. 4, thereby effecting a selected spacing of the jaws 2 and 8 for accommodating a selected size or shape of workpiece.

ln order to provide pivotal motion between the members 7 and 9 at a selected adjustment of the spacing of the jaws, the extension 9 is formed on its inner surface with a series of spaced apart substantially arcuate ribs 14 alternately arranged between the curved channels 15 respectively, and the member 7 is formed with a substantially arcuate rib 16 for travel along a selected channel and the adjacent ribs intermediate the selected channel when the handles are moved toward each other as in gripping a work piece in the jaws.

The member 7 being pivotally connected at 6 with the upper portion of the movable handle 5 and also pivotally movable about the axis of the bolt 1l adjustable along the slot 10, provides a leverage means whereby effective gripping pressure on the work piece may be imposed when the handles are moved relatively toward each other with a minimum of effort. By withdrawing the nut 12 along the bolt to reduce the thrust of spring 13 against the outer face of the member 7, the member 7 may be raised suiiciently to disengage the rib 16 from any one of the channels l5 in which it is engaged and then dropped into another selected channel of the series to space the jaws sufficiently to receive a work piece of given size and shape between the jaws preparatory to applying a gripping and locking pressure on it. Then the nut l2 is turned to increase the forces of compression of the spring 13 and thus draw the parts 7 and 9 into more intimate contact relationship with one another and to assure against displacement of the rib from its selected channel.

It is to be noted that the cylindrical rib is provided with a flat bearing surface 18 disposed at an angle for mating with a similar bearing surface 19 of any one of the selected channels l5 to assure against accidental displacement of the rib from its channel, yet providing a relatively large bearing area between the engaged surfaces of the rib and its channel as the handles are moved to and from piece gripping positions.

A toggle arm 20 is pivotally connected at its upper end as at 21 to the pivoted handle 5 and at its lower end portion is pivoted to a bolt shank 22 in the channel of the arm 1. A stop 23 may be formed on the toggle to engage the base wall of the channel of arm 5.

In operation, with the parts in position to receive a work piece as in 3, the axis of bolt l2, pin 6 and pin 21 are substantially as shown, that is, in substantial alignment along an imaginary straight line intersecting the axis of these members.

However, when a work piece W is inserted between the jaws and the handles are relatively moved toward each other to grip the work piece as in FIGS. l and 2, the axis 6 will be drawn beyond a dead center position and out of the area of the imaginary line as indicated in these figures to rotate the member 7 in a clockwise direction to draw the jaws into positive gripping relation with the piece W." To remove the work piece from the jaws, the handle 5 is moved on its axis in a clockwise direction as indicated in the dotted line position in FIG. l, to again return axis of pin 6 to the position shown in FIG. 3 causing the member 7 to be rotated in a counterclockwise direction releasing jaw 8 from its gripping position.

When the jaws are in gripping position, as in FIGS. l and 2, increased tension will be applied to spring 25, but when the jaws are released as described above, this increased tension of the spring will assist in drawing the handles in a direction toward each other.

By adjusting the bolt 3 in the end of handle 1 and locking it by means of the nut 4 against the end of the handle more or less locking pressure may be applied to the jaws through the toggle arm 20.

I claim:

1. Pliers comprising a fixed handle of channel cross section, a supporting extension laterally extending from the fixed handle, a member pivotally supported on said extension, a work piece gripping jaw on said fixed handle, a gripping jaw on said pivoted member cooperating with the fixed handle jaw for gripping a work piece therebetween, means pivotally connecting a movable handle with said member, a toggle bar pivotally connecting said movable handle with an end portion of the fixed channelled handle, said supporting extension having a flat outer surface and a closed longitudinal slot extending lengthwise of the extension, a series of substantially arcuate channels formed in the inner surface of said extension and forming spaced apart arcuate ribs between adjacent channels, said pivoted member having a substantially arcuate rib on its under surface for engagement in a selected channel on the extension, and means carried by the pivoted member consisting of a headed bolt passing through the slot, the headed portion overlying the flat outer surface of the extension, the shank portion of the bolt extending through the slot and through an opening in said pivoted member to allow longitudinal adjustment of the pivoted member along said slot for selecting the channel on the extension in which the rib on the pivoted member is to have sliding engagement, a compression spring exerting a force of compression against said pivoted member outer surface, and a nut adjustable along the bolt for applying compression to the spring to releasably maintain the rib on the pivoted member in the selected channel on the extension.

2. The invention defined in claim 1 in which the toggle bar lower end portion is in abutting engagement with an axially adjustable threaded member in the fixed handle lower end to thereby select the degree of locking pressure exerted through the toggle bar to the movable jaw when the handles are moved to close the jaws upon a work piece.

1l l l 

1. Pliers comprising a fixed handle of channel cross section, a supporting extension laterally extending from the fixed handle, a member pivotally supported on said extension, a work piece gripping jaw on said fixed handle, a gripping jaw on said pivoted member cooperating with the fixed handle jaw for gripping a work piece therebetween, means pivotally connecting a movable handle with said member, a toggle bar pivotally connecting said movable handle with an end portion of the fixed channelled handle, said supporting extensIon having a flat outer surface and a closed longitudinal slot extending lengthwise of the extension, a series of substantially arcuate channels formed in the inner surface of said extension and forming spaced apart arcuate ribs between adjacent channels, said pivoted member having a substantially arcuate rib on its under surface for engagement in a selected channel on the extension, and means carried by the pivoted member consisting of a headed bolt passing through the slot, the headed portion overlying the flat outer surface of the extension, the shank portion of the bolt extending through the slot and through an opening in said pivoted member to allow longitudinal adjustment of the pivoted member along said slot for selecting the channel on the extension in which the rib on the pivoted member is to have sliding engagement, a compression spring exerting a force of compression against said pivoted member outer surface, and a nut adjustable along the bolt for applying compression to the spring to releasably maintain the rib on the pivoted member in the selected channel on the extension.
 2. The invention defined in claim 1 in which the toggle bar lower end portion is in abutting engagement with an axially adjustable threaded member in the fixed handle lower end to thereby select the degree of locking pressure exerted through the toggle bar to the movable jaw when the handles are moved to close the jaws upon a work piece. 